hold

A hold is the interior cargo space of a vessel, located below the main deck. On a ship, it is the region where cargo sits directly above the bilge and below the waterline, sealed off by watertight bulkheads and hatch covers. The hold is exposed to moisture, salt spray, and condensation; it must be inspected, cleaned, and sometimes treated before loading to prevent cargo damage or spoilage.

Most seagoing vessels have multiple holds, numbered from bow to stern. A medium-sized general cargo ship might have five to eight holds, each served by its own hatch, winch, or crane system. Container ships and bulk carriers eliminate the traditional subdivision, instead using the entire cargo envelope as one or two continuous holds. The depth of a hold is measured from the tank top (the ceiling above the bilge) to the underside of the hatch covers; this dimension, along with beam and length, determines stowage capacity.

Condition and ventilation

A hold must be clean before cargo is loaded; residues from previous cargoes (grain dust, coal particles, oil films) can contaminate or damage new cargo, and may create fire or explosion risks in enclosed spaces. Ventilation is critical. Cargo holds are ventilated through air vents to manage humidity and temperature; inadequate ventilation causes condensation to form on cargo, especially when a warm, humid hold encounters cool air or cooler seawater. Ventilation may be passive (natural air circulation through vents) or active (powered ventilation systems).

Hold condition surveys are required before loading certain commodities. Shippers of grain, coffee, dried fruit, or other hygroscopic goods will specify that holds be clean and dry, often requiring certification. Steel holds can suffer from rust and corrosion; wooden ceiling boards or dunnage must be inspected for decay. If a hold has previously carried hazardous or odorous cargo (heavy fuel oil, phosphates, fish meal), it may require weeks of fumigation, heating, or aeration before reuse.

The term also applies loosely to cargo compartments in aircraft, though aviation usually employs the word compartment or specifies forward cargo hold or aft cargo hold. In older merchant navy usage, holds were sometimes called 'tween decks (between decks) if they occupied the space between two structural decks. The word derives from the Old English hold, meaning to grasp or contain.